#!/usr/bin/env python
# -*- coding: utf-8 -*-

# @Time     :2020/09/25
# @Author   :Changshu
# @File     :practice_168.py
# 进制转换，10进制转换为26进制
''''''

def convertToTitle(n:int)->str:
	if n<=0:
		return ''
	s=''
	while(n>0):
		n-=1
		s=chr((n%26)+65)+s
		n//=26
	return s

if __name__ == '__main__':
	# print(chr(65))
	print(convertToTitle(28))